1. Field of the Invention
The present invention relates to the field of space launch systems. More particularly the invention pertains to an apparatus and a method for delivering payloads from earth to orbit utilizing reusable components.
2. Description of the Prior Art
As the commercial, scientific, and military use of outer space continues to increase, the need for inexpensive transportation to earth orbit also increases. Present earth-to-orbit transportation systems include Expendable Launch Vehicles (ELV's) and the United States Space Shuttle.
Expendable Launch Vehicles are rocket systems that are discarded after a single launch. They tend to be expensive because an entirely new vehicle must be built and tested for each mission.
The Space Shuttle is a rocket system that utilizes reusable components. It consists of two solid rocket boosters, an expendable fuel tank, and a winged orbiter. The orbiter is capable of delivering cargo to earth orbit, and reentering earth's atmosphere for a glider type landing on a runway. It has the capability of returning cargo from space, but often lands with an empty payload bay. The use of reusable hardware was intended to decrease the transportation cost per pound of cargo compared with expendable launch vehicles.
Reusable earth-to-orbit launch vehicles, such as the Space Shuttle, must have means to reenter the earth's atmosphere and land on earth upon the completion of its orbital mission. To do this, the Space Shuttle requires systems for thermal protection and atmospheric flight. These systems are costly in terms of weight, overall vehicle performance, and vehicle maintenance requirements.
Other reusable space transport vehicles without a capability of reentry from orbit are generally known. One such vehicle, disclosed in U.S. Pat. No. 3,891,160 by Minovitch, is a microwave powered reusable orbiting space tug. Its purpose is to maneuver an object already placed in orbit by utilizing microwave beams directed from earth as a power source. Another idea for a space tug, called the Orbital Transfer Vehicle (OTV) by NASA, uses the Space Shuttle to deliver it to earth orbit and return it to earth. By using the Space Shuttle for its return to earth, the OTV itself does not need costly systems for reentry. Both of these vehicles operate only in space, and therefore cannot transport a payload from the earth's surface.